Fix initial_properties for minecarts

mods/ENTITIES/mcl_minecarts/init.lua

@@ -184,12 +184,14 @@ local entity_mapping = {}
 
 local function register_entity(entity_id, mesh, textures, drop, on_rightclick, on_activate_by_rail)
 	local cart = {
+		initial_properties = {
 			physical = false,
 			collisionbox = {-10/16., -0.5, -10/16, 10/16, 0.25, 10/16},
 			visual = "mesh",
 			mesh = mesh,
 			visual_size = {x=1, y=1},
 			textures = textures,
+		},
 
 		on_rightclick = on_rightclick,